Thursday, April 17, 2014

Most people now buy laptops for their computing needs and have to
make the decision between getting either a Solid State Drive (SSD) or
Hard Disk Drive (HDD) as the storage component. So which of the two is
the better choice, an SSD or HDD? There’s no straight-forward answer to
this question; each buyer has different needs and you have to evaluate
the decision based on those needs, your preferences, and of course
budget. Even though the price of SSDs has been falling, the price per
gigabyte advantage is still strongly with HDDs. Yet, if performance and
fast bootup is your primary consideration and money is secondary, then
SSD is the way to go. For the remainder of this article, we will make a
comparison of SSD and HDD storage and go over the good, the bad, and the
ugly of both.

What is an SSD?
We’ll make no assumptions here and keep this article on a level that
anyone can understand. You might be shopping for a computer and simply
wondering what the heck SSD actually means? To begin, SSD stands for
Solid State Drive. You’re probably familiar with USB memory sticks - SSD
can be thought of as an oversized and more sophisticated version of the
humble USB memory stick.
Like a memory stick, there are no moving parts
to an SSD. Rather, information is stored in microchips. Conversely, a
hard disk drive uses a mechanical arm with a read/write head to move
around and read information from the right location on a storage
platter. This difference is what makes SSD so much faster. As an
analogy, what’s quicker? Having to walk across the room to retrieve a
book to get information or simply magically having that book open in
front of you when you need it? That’s how an HDD compares to an SSD; it
simply requires more physical labor (mechanical movement) to get
information.

A typical SSD uses what is called NAND-based flash memory. This is a
non-volatile type of memory. What does non-volatile mean you ask? The
simple answer is that you can turn off the disk and it won’t “forget”
what was stored on it. This is of course an essential characteristic of
any type of permanent memory. During the early days of SSD, rumors
floated around saying stored data would wear off and be lost after only a
few years. Regardless, that rumor is certainly not true with today’s
technology, as you can read and write to an SSD all day long and the
data storage integrity will be maintained for well over 200 years. In
other words, the data storage life of an SSD can outlive you!
An SSD does not have a mechanical arm to read and write data, it
instead relies on an embedded processor (or “brain”) called a controller
to perform a bunch of operations related to reading and writing data.
The controller is a very important factor in determining the speed of
the SSD. Decisions it makes related to how to store, retrieve, cache and
clean up data can determine the overall speed of the drive. We won’t
get into the nitty-gritty details for the various tasks it performs such
as error correction, read and write caching, encryption, and garbage
collection to name a few. Yet, suffice to say, good controller
technology is often what separates an excellent SSD from a good one. An
example of a fast controller today is the SandForce SATA 3.0 (6GB/s) SSD
controller that supports burst speeds up to 550MB/s read and write
speeds. The next gen SandForce 3700 family of controllers was announced
in late 2013, and is quoted to reach a blistering 1,800MB/s read/write
sequential speeds as well as 150K/80K random IOPS.
Finally, you may be wondering what an SSD looks like and how easy it
is to replace a hard drive with an after-market device. If you look at
the images below, you’ll see the top and undersides of a typically-sized
2.5” SSD. The technology is encased inside either a plastic or metal
case and looks like nothing more than what a battery might:

SSD Top Side

SSD Bottom Side

The form factor of the SSD is actually the same as a regular hard
drive. It comes in a standard 1.8”, 2.5”, or 3.5” size that can fit into
the housing and connectors for the same-sized hard drives. The
connector used for these standard sizes is SATA. There are smaller SSDs
available that use what’s called mini-SATA (mSATA) and fit into the
mini-PCI Express slot of a laptop.

What is an HDD?
Hard Disk Drives, or HDD in techno-parlance, have been around for
donkey's years relative to the technology world. HDDs were first
introduced by IBM in 1956 - yes folks this is nearly 60-year old
technology, thank goodness vacuum tubes for TVs didn’t last so long! An
HDD uses magnetism to store data on a rotating platter. A read/write
head floats above the spinning platter reading and writing data. The
faster the platter spins, the faster an HDD can perform. Typical laptop
drives today spin at either 5400 RPM (Revolutions per Minute) or
7200RPM, though some server-based platters spin at up to 15,000 RPM!

The major advantage of an HDD is that it is capable of storing lots
of data cheaply. These days, 1 TeraByte (1,024 gigabytes) of storage is
not unusual for a laptop hard drive, and the density continues to grow.
However, the cost per gigabyte is hard to calculate now-a-days since
there are so many classes to consider, though it is safe to say that all
HDDs are substantially cheaper than SSDs. As a comparison, the popular
WD Black (1TB) goes for roughly $156 on most websites while the Crucial
M500 (960GB) and Samsung 840 EVO (1TB) SSDs go for $460 and $510
respectively, three times the price of the WD Black. So if you want
cheap storage and lots of it, using a standard hard drive is definitely
the more appealing way to go.

When it comes to appearance, HDDs essentially look the same from the
outside as SSDs. HDDs predominantly use SATA interface. The most common
size for laptop hard drives is the 2.5” form factor while a larger 3.5”
form factor is used in desktop computers. The larger size allows for
more platters inside and thus more storage capacity. Some desktop hard
drives can store up to 4TB of data! Below is an example of what an HDD
looks like using the Seagate Barracuda 3TB hard drive:

HDD Top Side

HDD Bottom Side

SSD Vs HDD Comparison
Now it’s time to do some comparisons and determine which might be
best for your individual needs - SSD or HDD? The best way to compare
items is a table with a side by side comparison of items in which a
green box indicates an advantage:

HDD doesn’t
produce much heat, but it will have a measurable amount more heat than
an SSD due to moving parts and higher power draw

Failure Rate

Mean time between failure rate of 2.0 million hours

Mean time between failure rate of 1.5 million hours

File Copy / Write Speed

Generally above 200 MB/s and up to 550 MB/s for cutting edge drives

The range can be anywhere from 50 – 120MB / s

Encryption

Full Disk Encryption (FDE) Supported on some models

Full Disk Encryption (FDE) Supported on some models

File Opening Speed

Up to 30% faster than HDD

Slower than SSD

Magnetism Affected?

An SSD is safe from any effects of magnetism

Magnets can erase data

If we tally up the checkmarks, the SSD gets 9 and HDD gets 3. Does
that mean the that an SSD is three times better than an HDD? Not at all.
As we mentioned earlier, it all depends on individual needs. The
comparison here is just to lay out the pros and cons for both options.
To aid you even more, here are some rules to follow when you decide
which drive is best for you:
An HDD might be the right choice if:

You need lots of storage capacity, up to 4TB (though SSDs are constantly narrowing this gap)

Don’t want to spend much money

Don’t care too much about how fast a computer boots up or opens programs - then get a hard drive (HDD).

An SSD might be the right choice if:

You are willing to pay for faster performance

Don’t mind limited storage capacity or can work around that (Again, SSDs are working on this “con”)

HDDs are still the popular choice for the majority of average
consumers, usually choosing the HDD as the storage option in their new
computer simply due to the much cheaper cost. However, more and more
consumers desire top computing performance and are opting for an SSD
inside their new setup or as an upgrade to their current one. As such,
SSDs are well on their way to becoming the mainstream, standard storage
mechanism, especially for laptops given the advantages they present for a
mobile device (they are currently the default storage device in the Ultrabook category). That said, there will always be a market for both HDDs and SSDs. The advent of mSATA SSD devices and hybrid drives that include both SSD and HDD features is another option for consumers seeking a bit of the best of both worlds, but that’s a topic for another day!
Curious about which SSD or hard drive to buy? Be sure to check out
our constantly updated leaderboard that has a breakdown of the best SSD in categories like value, mainstream and enthusiast.Consumer SSD ReviewsConsumer HDD Reviews